single wavelength detection can miss a co-eluting impurity that does not absorb there
Thread · #coa-reading · 2026-03-07
ok so gross mass on a jewellery scale plus
Spun off from a message in #coa-reading on 2026-03-07. 11 messages, 4 participants.
The message this came from
- nettle_notes — ok so gross mass on a jewellery scale plus the water content is enough to catch most underfills, n of 1 obviously 23:37
a lab that reports "greater than 98%" rather than a number is telling you they did not integrate carefully
the retention time on this one is different from the last lot, problem
water content is why an honest 10mg vial assays at 9.1. karl fischer titration, and most certificates omit it
check the lot
check the lot
weigh the vial
purity is not assay
net not gross
retention time shifts between runs are normal. relative retention time is the number to compare
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